Zinc supply

Zinc deficiency places an increased demand on selenium (Se) pools in daphnids. As little as 5 pg Se/L in zinc-free water eliminated overt cuticle damage and substantially increased reproduction, but did not alter the shortened life span. Cladocerans at the threshold of Se deficiency will become overtly Se deficient when zinc supplies are lacking (Keating and Caffrey 1989). Insufficient copper introduces cuticle problems in daphnids similar to those introduced by insufficient zinc or... 

In a separate experiment with zinc supplied at 9 ppm in all diets, the effect of increasing dietary calcium in calcium or magnesium precipitated tofu or egg white diets on weight gain and tibia zinc accumulation was tested. From Table IV it can be noted that the performance of tofu-fed rats relative to zinc carbonate-fed rats was quite similar at 0.4% total dietary calcium, but was reduced as dietary calcium was increased to 0.7% and to 1.2%. These results suggest that a poorly available calcium-zinc-phytate complex not present in the soy curd can form in the gastrointestinal tract when sufficient calcium is added to the diet. 

In vescicles from both zinc normal and zinc depleted rats, zinc transfer does not require energy. With vescicles from normal rats, the Jmax is 5.A nmoles per min, with a Km of O.Al mM. The Km is not changed, but the Jmax increases to 12.0 nmoles per min with vescicles from zinc depleted rats. Electrophoretic data suggests a change in brush border membrane protein composition occurs during zinc deficiency. These proteins could influence zinc uptake during a reduction in dietary zinc supply. 

The authors of the Dietary Reference Intakes (15) have concluded that reports of the effect of folic acid supplementation on the intestinal absorption of zinc are controversial, but that the recent literature shows that folic acid supplementation has either no effect or an extremely weak effect on zinc supply. 

Hume-Rothery Rules. It was from observations like these that Hume-Rothery was able to develop bis Intermetallic Compound Rules (1926). He showed that the above, and other, fi-phase abnormal valency intermetallic compounds, have one common characteristic they all hare three electrons to every two atoms. Tims, in CuZn the one copper atom provides one electron and the other atom—zinc—supplies two, so that the... 

Some 80% of the zinc available for recycling is currently recycled. Indeed, 30% of the world s zinc supply (2.9 million metric tonnes) is derived from recycled zinc. 

The zinc concentration of plants is species-specific, is dependent on the stage of vegetation as well as on zinc availability, and is influenced by the geological origin of the basic material for soil formation. Zinc supply is best from the weathering soils of syenite and phyllite (Siegert et al. 1986). 

The sensitivity of plants to zinc deficiency is variable among species. For example, oats, wheat, barley, and rye are not very sensitive, whereas potatoes, tomatoes, lucerne, and red clover have a medium sensitivity. By contrast, maize, hops, flax, and soybeans require a high level of zinc supply (Viets 1966 see also Table 3.29-3, p. 612 in Henkin 1984). Soils associated with zinc deficiency in plant are usually low in organic matter content and neutral to alkaline in reaction (Pais and Jones 1997). In Asia, zinc deficiency has been identified as the most widespread micronutritional disorder of wetland rice which occurs on sodic, calcareous, and poorly drained soils. 

SiEGERT E, Anke M, Szentmihalyi S, Regius A, Lokyay D, Pavel J, Grun M and Hora K (1986) The zinc supply of plants and animals in Middle Europe. In Anke M, Baumann W, Braunlich H, Bruckner C and Groppel B, eds. 5. Spurenele-ment-Symposium, pp. 487-493. Karl-Marx-Uni-versitat, Leipzig, Friedrich-Schiller-Universitat, Jena. 

Weigand E and Kiechgessnee M (1980) Total true efficiency of zinc utilization determination and homeostatic dependence upon the zinc supply status in young rats. J Nutr 110 469 - 480. 

Windisch W and Kiechgessnee M (1994b) Zinc excretion and the kinetics of zinc exchange in the whole-body zinc at deficient and excessive zinc supply 2. Effect of different zinc supply on quantitative zinc exchange in the metabolism of adult rats. J Anim Physiol Anim Nutr 71 123-130. 

In this voltaic cell, the oxidation of zinc supplies the electrons to light the bulb and reduce copper Ions. The spontaneous reaction continues until the zinc Is used up. 

MARKET FUNDAMENTALS AND THE EVOLUTION OF LEAD AND ZINC SUPPLIES... 

In this paper we will examine the evolution of lead and zinc supplies, the market factors influencing these supplies and will then seek to draw some conclusions from this analysis about future prospects for both industries. 

The United States has only 35% of the world s zinc supply, which currently stands at 1.8 gigatons (1.8 x 10 tons). Zinc-air battery designers predict that 21 months worth of global zinc production could be used to manufacture 1 billion 10 kWh zinc air cells. By contrast, it would take 180 years worth of lithium material to make an equivalent amount of Li-ion batteries. Because most of the supply of lithium is located outside of the United States, Li-ion batteries would have to made outside of the United States. In addition, Li-ion batteries require charging... 

Currently, the United States has more than 35% of the world s zinc supply. 

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